TW201319341A - Method to prepare a controllable skin layer hollow fiber membrane is developed and applies for dehydration of organic solution - Google Patents

Abstract

The method to prepare a controllable skin layer hollow fiber membrane is developed and applies for dehydration of organic solution. Hollow fiber membranes were prepared by spinning solution of polysulfone and sulfonated polysulfone in N-methyl pyrrolidone. Hollow fiber membranes spun at room temperature employing solvent spinning method. The spinning solutions were prepared from various concentration of polysulfone and sulfonated polysulfone in NMP. The spinning conditions were considered with various core liquid flow rate, spinning pressure, coagulation solvent, and post thermal conditions. The skin layer morphology can be determined by considering the composition of spinning solution, polarity of core liquid, flow rate of core liquid, spinning pressure, and coagulants in the coagulation bath. The skin layer morphology can be effectively improved by prolong the delay demixing behavior in coagulation bath. A suitable outer skin layer and inner skin layer hollow fiber membrane can be prepared by using the above preparing conditions. The pervaporation experiments were carried out to confirm the separation performance of hollow fiber membranes.

Description

Hollow fiber membrane preparation technology capable of controlling cortex and its pervaporation application method

The invention relates to a hollow fiber membrane preparation technology capable of controlling a skin layer and a pervaporation application method thereof, in particular to a preparation technology and a pervaporation method capable of forming a hollow fiber membrane having high flux, high selectivity and good skin layer. .

According to the film separation technology, it is a new separation technology in the rise of modern times. It has the functions of separation, concentration, purification and refining, and has the characteristics of simple operation, energy saving and low preparation cost. Its efficiency is higher than that of all separation technologies, and it is widely used in food, medicine, biology, environmental protection, chemical industry, water treatment, etc. field.

Membrane separation technology mainly uses the difference in the transmembrane rate of different components to achieve the separation effect. Therefore, the film used must be selective, that is, the film must preferentially permeate a certain component, such as a membrane with a suitable pore size, which can be used in water. The suspended particles block, allowing only water to pass through, achieving water purification purposes. The film can be divided into microfiltration membrane, ultrafiltration membrane, nanofiltration membrane and reverse osmosis according to different pore diameters. According to different materials, it can be divided into inorganic membrane and organic membrane. The inorganic membrane mainly contains ceramic membrane and metal membrane. The organic film is made of a polymer material such as cellulose acetate, aramid, polyether oxime or polyfluoropolymer, and the driving force of the substance through the film may be a concentration difference, a potential difference, a temperature difference or a pressure difference. In other forms, according to the aforementioned pore size, material and driving force, the current membrane separation technology can be roughly divided into microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrodialysis, gas separation, vapor permeation, pervaporation, thin film distillation, etc. The appropriate membrane separation technique is selected according to the characteristics of the medium to be separated.

Therefore, it can be seen that the performance of the film has a great influence on the separation effect, so many scholars have been working on the development of the film modification technology to improve the film separation efficiency. The separation efficiency of the membrane is mainly determined by the permeation amount of the separation medium and the selectivity to the species to be separated. The advantage of separation efficiency plays an important role in determining the separation cost in various separation programs, so the good membrane has superior separation performance. Cost-effective separation of the mixture, in addition to high permeability, must also have good selectivity, but the two can not always take into account, such as: flat film has high selectivity, but also has low permeability rate defects, with high choice Sex film, in a limited space, often can not provide a higher amount of permeation, and the existing hollow fiber [Hollow fiber] film can overcome the low low permeability problem by increasing the effective film area or reducing the thickness of the film. The unit volume can provide a large working area, and can also provide maximum production efficiency in a limited space, while utilizing its geometry, high mechanical strength and support capacity, but the existing hollow fiber [Hollow fiber] film It is difficult to use with pervaporation technology, which is the most common in membrane separation technology. Separation method, especially for the separation of liquid mixtures such as azeotrope, boiling point isomers or heat sensitive substances, therefore, how to prepare a hollow with high flux, high selectivity and good cortical structure Hollow fiber film is the focus of research and development of thin film technology today and in the future.

Therefore, the inventors of the present invention have in view of the difficulty in using the hollow fiber membrane technology in the pervaporation method, and have been assisted by the manufacturing and design experience and knowledge of the related fields for many years, and have been invented for the existing hollow. The invention has been developed by making fiber thin film production and how to cooperate with the application of the pervaporation method to make updated research and development improvements.

The invention relates to a hollow fiber membrane preparation technology capable of controlling a skin layer and a pervaporation application method thereof, and the main purpose thereof is to provide a hollow fiber membrane which can form a high flux, high selectivity and good skin layer. Preparation techniques and pervaporation methods.

In order to achieve the above-mentioned object, the inventors have studied the following techniques for preparing a hollow fiber membrane capable of controlling a skin layer, and the following steps are carried out:

A. Disposal of casting solution: Add one of polyfluorene [PSF] polymer and sulfonated polyfluorene [SO ₃ H-PSF] to nitrogen-methyltetrahydropyrrolidone [NMP] to prepare a concentration of the polymer spinning solution;

B. preparing a spinning solution: adding a core liquid to the spinning solution, and setting the flow rate of the core liquid and the pressure of the casting film;

C. Spinning film formation: The spinning solution is spun in a spinning device, so that the spinning solution and the core liquid are squeezed out from the spinning nozzle, and then solidified into a film by entering a coagulant of different polarity.

The hollow fiber membrane preparation technique for controlling the skin layer as described above, wherein the step of preparing the spinning solution further adds chloroform [CHCl ₃ ] to the spinning solution.

The hollow fiber membrane preparation technology capable of controlling the skin layer as described above, wherein the step of preparing the spinning solution comprises a solution of water, methanol, ethanol, n-propanol, n-butanol and n-hexane. One.

The hollow fiber membrane preparation technique capable of controlling the skin layer as described above, wherein the coagulant used in the step of spinning the film formation comprises one of water, methanol, ethanol, n-propanol and n-butanol.

The hollow fiber membrane preparation technology capable of controlling the skin layer as described above, wherein the hollow fiber membrane preparation technology capable of controlling the skin layer and the pervaporation application method further comprise the step of encapsulating the hollow fiber membrane after the spinning film formation, The plurality of hollow fiber membranes are assembled into a bundle and placed in a circular hole formed in the base to form a module.

The present inventors have developed a method for applying a hollow fiber membrane capable of controlling a cortex to pervaporation to feed back the preparation of the hollow fiber membrane, which is mainly provided with a pervaporation apparatus, and the pervaporation apparatus is provided with a permeation chamber, and The permeation chamber is divided into two chambers by a fixing member, and the hollow fiber membranes produced in the first aspect of the above patent application are assembled to the fixing member.

Therefore, in the molding of the hollow fiber membrane, the parameters of the spinning solution, the type of the core liquid, the flow rate, the pressure of the casting film and the coagulant, and the post-filming heat treatment method are controlled to improve the retardation setting effect of the hollow fiber membrane molding. Furthermore, the structure of the inner and outer skin layers of the hollow fiber membrane is controlled, and by the pervaporation experiment, in the actual implementation, the optimal parameter setting value is further obtained to surely prepare a hollow with high flux, high selectivity and good cortical structure. Fiber film.

In order to make the technical means of the present invention and the effects thereof can be more completely and clearly disclosed, the following is a detailed description. Please refer to the disclosed drawings and drawings:

First, referring to the first figure, the hollow fiber membrane preparation technology of the controllable skin layer of the present invention comprises the following implementation steps:

A. Preparation of the membrane material: 3 g of polyfluorene [PSF] polymer was placed in a serum bottle, and 20 ml of chloroform [CHCl ₃ ] was added to the solvent to be dissolved, and then in a high evacuation air extracting cabinet, Mixing chlorosulfonic acid with 5 ml of chloroform [CHCl ₃ ] with 0.15 ml, 0.25 ml, 0.35 ml, 0.45 ml and 0.55 ml, and adding chlorosulfonic acid solution to the polymer solution. After stirring for 1-2 hours at room temperature with a magnetic stirrer, methanol was added, and the sulfonated solution after the reaction was ion-exchanged, soaked for 24 hours, washed with reverse osmosis [RO] water and soaked for 24 hours. Drying for another 24 hours, to prepare sulfonated polyfluorene [SO ₃ H-PSF];

B. Configure the casting solution: weigh the desired polyfluorene [PSF] polymer and sulfonated polyfluorene [SO ₃ H-PSF], place them in a serum bottle, and add solvent 25 ml of nitrogen-methyl four. Hydropyrrolidone [NMP], prepared into a polymer spinning solution of the desired concentration, and stirred well for 24 hours with a magnetic stirrer, left to stand at room temperature, and the bubbles in the spinning solution are completely driven off;

C. Preparation of a spinning solution: a polyfluorene/nitro-methyltetrahydropyrrolidone [PSF/NMP] spinning solution at a concentration of 22.7-26% by weight [wt%], adding 0-8 weight percent concentration [wt %] chloroform [CHCl ₃ ] with deionized water as the Bore liquid and set the flow rate to 5 ml/min, and deionized water as the external coagulant, and cast The membrane pressure [Dope extrusion pressure] was set to 0.5-4.0 atm [atm], the spinneret diameter [Spinneret diameter] outlet diameter/inlet diameter [OD/ID] was set to 0.53/0.25 mm, and the air gap [Air gap] was set to 0-25 cm, according to the above spinning parameters, the desired spinning solution;

D. Spinning film formation: hollow fiber is prepared by wet phase conversion method. Before preparing hollow fiber membrane, the spinning nozzle is washed with reverse osmosis water and rinsed with water. After drying, the clarified spinning is completed after standing. The appropriate amount of the solution is poured into the tank, and the hollow fiber membranes are respectively spun by a spinning apparatus by a Dry/wet Spinning process or a Wet spinning process, if dry/ In the wet spinning method, the spinning solution [Dope] and the boring liquid [Bore liquid] are squeezed out by the spinner [Spinneret] to form a nascent hollow fiber membrane [nascent Hollow fiber membrane], after a period of gas distance [ Air gap], and then enter the coagulant to form a film. If it is a wet spinning method, the spinning solution and the core liquid are squeezed out from the spinning nozzle, and then the hollow fiber membrane is formed in the coagulant, and the hollow fiber membrane is formed. After standing in deionized water for three days, and then soaking the methanol for 2 hours, the excess solvent on the film was removed, the hollow fiber membrane was taken out and dried in the air to complete a film forming process, and finally the hollow fiber membrane was placed in a vacuum oven. Dry at room temperature for 24 hours;

E. Packaging hollow fiber membrane [Hollow fiber]: The five hollow fiber membranes are assembled into a bundle, which is placed in a circular hole on the aluminum base, and the round hole on the base and the other end of the hollow fiber membrane are epoxy resin [Epoxy] Adhesives: KS Bond EP231] seals to form a pervaporation module, each hollow fiber membrane effective length of 8 cm.

Accordingly, referring to the second figure, the present invention prepares a spinning solution by using polysulfone (PSF) and nitrogen-methyltetrahydropyrrolidone [NMP], and using solvent chloroform [CHCl ₃ ] as an additive. The addition of the non-hydrophilic chloroform [CHCl ₃ ] is a delayed stereotyping effect which can be produced when the hollow fiber membrane is solidified, and the giant pore structure of the hollow fiber membrane can be significantly restricted by the delayed stereotype effect, and the cortex is made The thickness of the dense layer is increased, as shown by the second graphs (A) to (E), as the concentration of the added chloroform [CHCl ₃ ] is gradually increased, the thickness of the dense layer of the cortex is increased.

Furthermore, in the molding process of the hollow fiber membrane, appropriately increasing the pressure of the casting solution of the spinning solution can increase the release amount of the polymer solution, and affect the total film thickness during the film formation process, and the mold pressure increases moderately. The thickness of the hollow fiber membrane will be thickened. Please refer to the third figure for the electron microscope image of the hollow fiber prepared by the wet spinning method for different casting pressures [SEM image], from the third figure (A) to (D) The casting film pressure is gradually increased, and the preparation condition is polyfluorene/nitro-methyltetrahydropyrrolidone [PSF/NMP] spinning solution, and deionized water is used as the core liquid to set a fixed flow rate, and the external coagulant is The deionized water solution, such as the film prepared in the third figure, has a support layer of a high-porosity double-finger giant pore structure and has a cortical structure, and it can be observed that the hollow fiber membrane clearly exhibits a double-finger structure, and when the pressure is extracted When large, the film thickness of the fiber membrane increases slightly with the increase of the extraction pressure. The reason is that the pressure of the polymer cast film increases, and the thickness of the polymer cast film is also increased. Therefore, the overall film thickness is slightly increased, and the other fiber film is obviously double-finger. The cause of the structure is the liquid Both the external coagulant and the external coagulant are water. Therefore, when the aqueous solution and the spinning solution are phase-converted, they have the same conditions and speed. Once the concentration of the polyfluorene polymer in the solution becomes large and gradually solidifies, the finger-shaped giant pores are The aqueous phase grows in the direction of the organic phase to form a finger-like macroporous structure. And as the pressure of the casting film increases, the spinning speed increases, the contact time with air is shortened, and the surface solvent evaporation time becomes shorter, so that a double giant pore layer is formed at 4 atm [atm], mainly because the mold pressure is increased. The spinning speed is quite fast, and the contact time with air is shortened, so that the rate of conversion between the outer skin layer and the endothelial layer is equivalent, thereby forming a double giant pore layer.

The invention further prepares hollow fiber membranes with different polymer concentration spinning solutions, as shown in the fourth and fifth figures, the concentration of the spinning solution is gradually increased from (A) to (D), and the concentration of the spinning solution can be seen. From a concentration of 19% by weight [wt%] to a concentration of 26% by weight [wt%], it can be seen that the giant pores of the cortex are inhibited from forming a support layer of a sponge-like structure, and are clearly visible from a concentration of 21.5% by weight [wt%]. The cortex gradually forms a support layer and a dense skin layer of the sponge-like structure, which is presumed by the solubility parameter. When the concentration of the polymer increases, the percentage of the solvent decreases, so that the conversion rate of the solvent and the coagulant decreases, so the height is high. The molecular concentration is increased, so that the film formation rate of the film is lowered, and the defects on the thickened structure of the dense layer are reduced. Therefore, when the spinning condition is fixed, the spinning speed is slow when spinning at a low concentration of the polymer spinning solution, so that the spinning speed is slow. The film thickness is relatively thin. Therefore, it can be known from the above that the thickness of the dense skin layer increases and thickens with the polymer concentration of the spinning solution, and the low concentration of the casting film liquid has a thick fiber film thickness, and the endothelial layer only has a thick layer. Into the thin skinned.

Further, the present invention prepares a hollow fiber membrane at different air gaps, as shown in the sixth figure, the (A) to (E) air gap is gradually increased, and the air distance is shown in the figure. When the height of [Air gap] increases, the finger-shaped giant pores of the film support layer are suppressed, and the microporous structure of the sponge-type support layer is gradually formed, because the solvent of the outer skin layer is chloroform [CHCl ₃ ] when the air gap increases. The solvent evaporates quickly, and the polymer concentration of the outer skin layer increases, the concentration of the polymer solution in the outer skin layer increases to form a polymer rich phase, and the as-spun hollow fiber is formed, and then the as-spun hollow fiber enters a desolvent water [nonsolvent] coagulant. When forming into the coagulant, due to its delayed shaping effect, the dense skin layer is prepared to reduce the pinhole on the surface, thereby forming a support layer and a dense skin layer of the sponge layer, and the endothelial layer is a thumb structure. Hollow fiber membrane.

Therefore, it can be seen from the above-mentioned embodiments that the hollow fiber membrane preparation technique of the present invention utilizes the addition of chloroform [CHCl ₃ ] to the spinning solution to produce a delayed stereotypic effect on the outer cortex of the hollow fiber membrane, and to control the spinning. The concentration of the solution, the pressure and flow rate of the casting film, and the spinning conditions such as changing the air gap in the dry/wet spinning process, to achieve changes and to improve the delayed stereotyping effect of the outer cortex, in order to facilitate the preparation of a sponge-like dense outer skin layer structure.

Referring also to the seven figures, the present invention further utilizes different polar external coagulants to produce a delayed setting effect of the outer skin layer and to prepare a film structure of different pores, which is a polyfluorene/nitrogen-methyl group. Hydropyrrolidone [PSF/NMP] is a spinning solution, and deionized water is used as a fixed core liquid [Bore liquid], and the flow rate of the fixed core liquid, and methanol, ethanol, n-propanol, n-butanol, 95 volume ratio [v/v] n-butanol/water, 90 volume ratio [v/v] n-butanol/water, 85 volume ratio [v/v] n-butanol/water or 80 volume ratio [v/v] n-butanol /Water, etc. is an external coagulant to prepare the desired hollow fiber membrane, as shown in Figure 8, for different polar external coagulant pairs of polyfluorene/nitro-methyltetrahydropyrrolidone [PSF] /NMP] is an electron microscope image [SEM image] of the influence of the hollow fiber membrane structure of the spinning solution, and the preparation conditions are controlled to be a polyfluorene/nitro-methyltetrahydropyrrolidone [PSF/NMP] as a spinning solution. Deionized water is used as the fixed core liquid [Bore liquid], and the flow rate of the fixed nucleus is water, methanol, ethanol, n-propanol, n-butanol as external coagulant, when the inner/outer cortex is For the core liquid and the external coagulant, the conversion speed between the external and internal phases is equivalent, and it is known from the light penetration diagram that when water is used as the external coagulant [as shown in the eighth figure (A)], it is immediately The phase separation is easy to obtain the structure of the giant pores. Therefore, when the external coagulant and the core liquid are both aqueous solutions, the prepared fiber membrane has a high porosity and a double-finger giant pore structure, and when methanol is used as an external condensation. The agent [as shown in the eighth figure (B)] can be seen that the membrane structure still exhibits a mega-finger giant pore structure. This point can be determined by the light penetration diagram to confirm that methanol is a coagulant, which belongs to immediate phase separation, so the outer layer The giant pore structure of the thumb is still present, and when ethanol is used as the external coagulant [as shown in the eighth figure (C)], the giant pore structure of the outer layer of the thumb is suppressed, which is known by the light penetration map. The phase separation rate is slower than that of water and methanol, and is closer to the delayed phase separation. The endothelium still uses water as the core liquid. It is an immediate phase separation. The phase separation rate of the inner/outer cortex is inconsistent, so that the pore structure of the outer cortex is inhibited. sea Shape and part of the macroporous structure, while the endothelial layer is still the structure of the m-finger giant pores, when further low-polar solution n-propanol [as shown in Figure 8 (D)], n-butanol [such as the eighth figure (E) is an external coagulant. It can be seen that the giant pores in the outer layer inhibit the formation of a sponge-like structure. According to the light penetrability test, when n-propanol and n-butanol are used as coagulants, the phase separation rate can be reduced. The phenomenon of delayed stereotyping belongs to delayed phase separation, which forms a sponge-like structure in the outer cortex. The endothelium maintains giant pores because water is still used as the core. It is known from the research results that the phase transition rate of the inner/outer coagulant is inconsistent. Thus, a structure in which the outer layer is delayed-phase-separated into a sponge morphology is formed, and the endothelial layer is immediately phase-separated into a macroporous structure. Therefore, according to the above results, it can be seen that when water and methanol are used as a coagulant, the phase separation is immediate, and when n-butanol is used as a coagulant, the phase separation is delayed, and as the polarity of the alcohol decreases, the phase separation rate decreases. Delaying the effect of shaping, thereby using different external polarities to control the outer layer of the hollow fiber membrane to produce different degrees of delayed shaping effect, please refer to the nine figures, it can be clearly seen that different polar external coagulants [ External coagulant] The effect on the thickness of the dense layer of the hollow fiber membrane outer skin layer.

Referring also to Fig. 10, the present invention further delays the shaping effect of the endothelial layer with different polar liquids [Bore liquid], which is polyfluorene/nitro-methyltetrahydropyrrolidone [PSF/NMP], or sulfonate. Acidified polyfluorene/nitro-methyltetrahydropyrrolidone [(SO ₃ H-PSF)/NMP] is a spinning solution, deionized water, methanol, ethanol, n-propanol, n-butanol, n-butanol and N-hexane is the core liquid [Bore liquid], please refer to the figure shown in Figure 10. When the inner/outer skin layer uses water as the external coagulant and the core liquid, the film is prepared because the external and internal phases are converted at the same speed. a giant pore structure having a high porosity and a double-finger shape [as shown in Figure 11 (A)], and when the endothelial layer is methanol as shown in Figure 11 (B) It was found that ethanol (as shown in Figure 11 (C)], n-propanol, n-butanol as the core liquid, its endothelial pores were completely inhibited to form a sponge-like support layer, in which n-propanol [such as the tenth Figure (D) shows that n-butanol [as shown in Figure 11 (E)] is a core liquid, which further forms a dense endothelial layer. This structure is in contact with both light transmission and light penetration tests. Should be, when the water is the core liquid, the non-solvent has a lower affinity with the solvent nitrogen-methyltetrahydropyrrolidone [NMP] solubility parameter, but the water molecular structure is smaller and easier to diffuse into the spinning The inside of the silk solution forms an instant phase separation to form a giant pore. When the methanol is used as the core liquid, the coagulant/solvent resolution parameter decreases the affinity, but the molecular size of the methanol increases slightly, making it difficult to diffuse into the spinning solution. Therefore, compared with water, the membrane structure of the macroporous macroporous shape of the endothelium is inhibited to form a spongy structure, and a part of the macroporous structure is formed, and ethanol, n-propanol and positive in the solvent polarity are used. Butanol not only inhibits the formation of a sponge-like support layer structure but also exhibits a dense skin layer. According to the light penetrability test, it is shown that the reduction of the polarity of the alcohol does have a delayed type, because the difference in molecular size diffusion ability is inferior to the non-solvent/solubility parameter. Therefore, when a low-polarity alcohol is used as a coagulant, the porosity of the film is lowered due to difficulty in entering the spinning solution, thereby forming a thick and dense endothelium layer, and the outer skin layer is a coagulant due to the use of water. Maintaining mega-hole, the inner / outer phase conversion rate inconsistent coagulant thus forming the inner skin-delayed phase separation of a sponge-like structure, the outer skin layer immediately formula phase separation of giant porous structure. It can be seen that when water and methanol are used as the core liquid, the thickness of the dense layer of the endothelial layer is thin because of the immediate phase separation, and the force of the affinity and molecular size diffusion force when ethanol is used, There is a delayed setting effect, but the thickness of the dense layer is not obvious. The low-polarity alcohol n-propanol and n-butanol are used as the core liquid to reduce the phase separation rate, which is a delayed phase separation, and a dense thick endothelium layer can be obtained. Accordingly, it is also possible to delay the stereotype effect on the inner cortex of the hollow fiber membrane by controlling the different polar liquids [Bore liquid], and the addition of chloroform [CHCl ₃ ] or the external coagulant of different polarities [External coagulant] In order to jointly prepare the outer skin layer as a sponge-like dense skin structure, and the endothelial layer is a thumb-like structure, a hollow fiber [Hollow fiber] film with high flux, high selectivity and good skin layer.

Thereby, referring to the twelfth figure, the hollow fiber membrane produced by the above hollow fiber [Hollow fiber] film preparation technology of the present invention is further applied to a pervaporation apparatus which is provided with a permeation chamber [ Cell] (1), and fixing the hollow fiber membrane (3) to the permeation chamber [Cell] (1) with an O-ring (2) to partition the permeation chamber (1) into upper and lower chambers, and The operating pressure is 3-5 mmHg [mmHg], the feed concentration range is adjusted, the temperature range is 25 ° C, and the hollow fiber membrane (3) module to be tested is installed in the second chamber, and the activation is about 30 minutes after stabilization. Formal sampling for 60 minutes, the feeding solution directly contacts the hollow fiber membrane (3) during operation, and penetrates into the hollow part of the inside of the membrane from the outer surface of the hollow fiber membrane (3), and then exits from the outlet end of the hollow fiber membrane (3). a collector [trap] (4) [as shown in Figure 13] with a liquid nitrogen [-196 ° C], etc., to collect the material that has permeated through the membrane, and the permeate is completely thawed by gravimetric method and gas. The color layer analyzer [GC] measures the weight and concentration of the hollow fiber membrane (3), and the permeability of the hollow fiber membrane. [Permeation Rate]P, and the selection ratio [Separation Factor]α _A/B , can be calculated by the following formula:

;among them:

P: transmittance [g/m2.h, g/m ² ×h]

W: the weight of the species through the hollow fiber membrane [g, g]

A: effective hollow fiber membrane area [m2, m ² ]

t: operation time [hours, hr]

α _A/B = (Y _A /Y _B )/(X _A /X _B ); where:

Y _A , Y _B : Permeate water, ethanol concentration

X _A , X _B : water and ethanol concentration in the feed

A: The species that are preferred for transmission.

Accordingly, when the present invention is applied to the pervaporation apparatus described above by adding a hollow fiber membrane formed by adding chloroform [CHCl ₃ ] to a spinning solution, as shown in Fig. 14, it is 26 weight%. Concentration [wt%] of polyfluorene/nitro-methyltetrahydropyrrolidone [PSF/NMP] spinning solution was added with 0-7.4 volume percent [vol%] chloroform [CHCl ₃ ] hollow fiber membrane at 25 ° C Separation of 90% by weight concentration [wt%] of ethanol/water solution, it can be seen from the fourteenth figure that there is no significant change in the amount of permeation, which is mainly due to the suppression of finger-shaped giant pores in the membrane. It is known that there is no significant change in the inhibitory effect, and there is no significant change in the amount of permeation, but in terms of its selectivity to water, as the added chloroform [CHCl ₃ ] increases to 1.9- 5.6 volume percent [vol%], the water selectivity system has an upward trend, because the addition of chloroform [CHCl ₃ ] to the polythene casting solution liquid, the prepared asymmetric polyfluorene film structure type Giant pores are inhibited and formed in the skin layer of asymmetric polysilicon film during film formation The dense skin layer is thus improved, and the selection ratio of water is increased. When chloroform [CHCl ₃ ] is added to the mold liquid to 7.4 volume percent [vol%], the film structure is significantly collapsed, resulting in a decrease in separation performance.

Referring also to the fifteenth figure, the hollow fiber prepared by changing the casting film pressure is applied to the pervaporation apparatus, and the 90% by weight concentration [wt%] of the ethanol/water solution is separated at 25 ° C, when the casting pressure is set. For 0.5-2.0 atm [atm], as the atmospheric pressure rises upward, the amount of permeation decreases, because the casting film pressure increases during casting, the film produced has a thicker film thickness, and the other is cast. The increase of membrane pressure during the casting process increases the spinning speed and makes the polymer chain more tidy and stable, thus causing the penetration of the polymer to decrease. The selectivity of pervaporation is known from the fifteenth figure. The main reason for this is that the pores are still dominated by open pores, so although the amount of permeation decreases, the selectivity does not have a significant improvement.

Referring also to Fig. 16, the hollow fiber membrane prepared by changing the flow rate of the spinning solution is applied to a pervaporation apparatus, and the 90% by weight concentration [wt%] of the ethanol/water solution is separated at 25 ° C. It can be seen from the figure that the pressure of the casting film is increased from 1 atm [atm] to 2 atm [atm], and the amount of permeation is slightly reduced because the film thickness is increased when the pressure of the casting film is increased, and the polymer chain is tighter. The amount of permeation is slightly reduced, and when it is increased to 3-4 atmospheres [atm], the contact time of the film with air is shortened, and the surface solvent evaporation time is shortened, so that the thickness of the sponge layer of the surface layer is reduced, and up to 4 At atmospheric pressure [atm], the casting speed is faster, because the solvent volatilization inhibition time is quite short and the double macroporous structure is formed, so that the permeation amount is increased, the separation coefficient is lowered, and the pressure increases with the casting film and the air. The shortening of contact leads to shortening of the solvent evaporation time of the surface layer, so that the surface skin layer is no longer dense, so that the sponge-like support layer has giant pores to form a double macroporous structure, thereby lowering the pervaporation separation coefficient.

Please also refer to the effect of the polymer concentration spinning solution on the pervaporation separation efficiency of the hollow fiber membrane as shown in Fig. 17, when the polymer concentration of the spinning solution is increased from 19% by weight [wt%] to 26% by weight. [wt%] It can be seen that the giant pores in the endothelial layer are inhibited to form a support layer of a sponge-like structure, and a denser endothelial layer is formed at a higher polymer concentration, and the heat treatment time is changed when the hollow fiber membrane is heat-treated. The longer the membrane, the lower the transmittance of the hollow fiber membrane decreases with the treatment time, and the selectivity to water increases. This phenomenon is due to the increase in the heat treatment. Therefore, it has a denser and more stable structure. Therefore, when the pervaporation process is operated, the selectivity to water increases and the transmittance decreases until the transmittance is stabilized. At this time, the film is most selective and stable. Transmittance.

Referring also to Fig. 18, a hollow fiber membrane made by using a change in air gap is applied to a pervaporation apparatus at a concentration of 90% by weight [wt%] of ethanol/water solution at 25 °C. Separation, it can be seen from the figure that as the height of the air gap increases, the permeability of the hollow fiber membrane increases and the selectivity to water decreases, and the height of the air gap increases, although its giant pores It is inhibited and produces a sponge-like support layer structure, which causes the surface structure to form a tight and continuous structure due to gravity, and the phenomenon of surface pinholes increases with the increase of air gap [Air gap] Obviously, therefore, as the formation of the air gap increases, the amount of hollow fiber membrane permeation increases, and the selectivity to water decreases.

Please refer to the nineteenth figure, when adding 5.6 volume percent [vol%] of chloroform [CHCl ₃ ] to the spinning solution, and making the air gap [Air gap] change, the hollow fiber membrane is made at 25 ° C. The separation of 90% by weight concentration [wt%] of ethanol/water solution is carried out. From the fifteenth figure, the penetration amount increases with the increase of air gap [Air gap], and the selectivity to water increases significantly. When there is no air gap [Air gap], the film is double-layered giant hole, which makes it less separable. When the air gap is 10-25 cm, the giant hole of the outer layer is suppressed. The structure of the sponge layer is formed, and the surface layer of the fiber membrane forms a distinct dense skin layer, thereby improving the separation efficiency. When the height of the air gap is 25 cm, the selectivity to water is lowered, and the transmittance is increased. The main reason is that when the height of the air gap is too long, it is affected by gravity stretching and solvent evaporation. In this case, the surface skin layer cannot maintain a continuous dense structure, and the surface thereof exhibits pinholes. It can be seen that in the process of film formation of hollow fiber membranes Moderate-gas from the length of the outer structure were prepared, of good surface skin.

Please refer to the twentieth figure, and the hollow fiber membrane prepared by external coagulant such as water, methanol, ethanol, n-propanol and n-butanol in a pervaporation apparatus at a concentration of 90% by weight at 25 ° C [ The ethanol/water solution of wt%] is separated. It is known from the pervaporation test that the hollow fiber membrane prepared by the external coagulant is increased in transmittance, and the separation efficiency is worse than that when water is the external coagulant. It can be inferred from the solvent/non-solvent dissolution parameter difference and molecular size, because the methanol and nitrogen-methyltetrahydropyrrolidone [NMP] solubility parameter difference is lower than that of water, and the solvent affinity is higher. The rate is also fast, and in terms of molecular size, the methanol molecule is slightly larger than the water molecule, but its molecular diffusion is not much different from that of the water molecule, so the solvent/nonsolvent affinity is high, and the non-solvent molecules diffuse into the spinning solution. The rate is fast, and the force of the hollow fiber membrane prepared by using methanol as an external coagulant is less dense than that of water, resulting in a difference in separation efficiency compared with the hollow fiber membrane prepared by using water as an external coagulant. When ethanol, n-propanol and n-butanol are external coagulants, the amount of permeation gradually decreases and the separation efficiency increases. Due to the retardation of the film, the molecular structure of the external coagulant is not easy to enter into the spinning solution. Phase separation, thus forming a dense outer skin layer to increase the permeation and evaporation separation efficiency, and it can be found that when the ethanol is an external coagulant, the thickness of the outer layer of the outer layer is not significant, but the permeation evaporation can improve the separation efficiency. When ethanol is used as the external coagulant, the outer skin layer forms part of the sponge morphology and the structure of the macropores, and the sponge-like support layer structure formed may be a closed pore. Therefore, it is known from the results of the research. The hollow fiber membrane prepared by the alcohol as the external coagulant has the best separation efficiency, and the permeation amount and separation performance are 103.9 g/ m ^{2 ,} hour [g/ m ² h] and 99.92%, respectively, which are obtained by the pervaporation test. It is known that external coagulants of different polarities of water, methanol, ethanol, n-propanol and n-butanol have the pervaporation separation efficiency in the order of n-butanol>n-propanol>B >Water> methanol, methanol permeation amount is sequentially>water>ethanol>n-propanol> n-butanol.

Please refer to the twenty-first figure, and the hollow fiber membrane prepared from water, methanol, ethanol, n-propanol, n-butanol and n-hexane, etc., in a pervaporation apparatus, in 25 Separation of 90% by weight concentration [wt%] of ethanol/water solution at °C, the transmittance of the hollow fiber membrane with the core liquid being methanol increased, and the separation efficiency is worse than that of water as the core liquid. When methanol is used as the core liquid In the film formation, the solubility parameter difference with the nitrogen-methyltetrahydropyrrolidone [NMP] solvent is lower than that of water, and the difference in molecular size diffusion is known from the light transmission map. When methanol is a coagulant, it is an immediate phase separation, thus forming a thinner dense layer and a part of the macroporous sponge-like support layer structure in the endothelial layer, resulting in a difference in pervaporation separation efficiency compared to water as a core liquid, and when ethanol When n-propanol and n-butanol are the core liquid, the amount of permeation gradually decreases and the separation efficiency increases. Due to the retardation of the film, the molecular structure of the core liquid is not easy to enter the spinning solution, thus making the inner layer dense layer. Thicker thicker, resulting in pervaporation separation You can increase, decrease transmission rate.

As can be seen from the above structures and embodiments, the present invention has the following advantages:

1. The hollow fiber membrane preparation technology of the controllable skin layer of the invention utilizes the addition of chloroform to the spinning solution to produce a delayed stereotype effect on the outer cortex of the hollow fiber membrane, and to control the pressure and flow rate of the casting solution by controlling the spinning solution. And changing the spinning conditions in the dry/wet spinning process to change and enhance the delayed stereotyping effect of the outer cortex, and prepare a sponge-like dense outer skin structure.

2. The hollow fiber membrane preparation technology of the controllable skin layer of the present invention further produces a delayed setting effect on the outer skin layer of the hollow fiber membrane by controlling external coagulants of different polarities, and controls the pressure and flow rate of the casting solution by using the spinning solution. And changing the spinning parameters such as the air distance in the dry/wet spinning process to change and enhance the delayed stereotype effect of the outer cortex, and prepare a sponge-like dense outer skin structure.

3. The hollow fiber membrane preparation technology of the controllable skin layer of the invention further controls the different polar core liquid to produce a delayed stereotype effect on the inner layer of the hollow fiber membrane, and utilizes the control film pressure and flow rate of the spinning solution, and The spinning conditions such as the gas distance in the dry/wet spinning process are changed to change and enhance the delayed stereotypic effect on the inner cortex to prepare an endothelial layer having a thumb-like structure.

4. The hollow fiber membrane preparation technology of the controllable skin layer of the invention utilizes the addition of chloroform or the external coagulant of different polarity in the spinning solution to produce a delayed stereotyping effect on the outer cortex of the hollow fiber membrane, and further by controlling Different polar core liquids have a delayed shaping effect on the endothelial layer of the hollow fiber membrane, and further control the pressure and flow rate of the spinning solution casting film, and change the spinning conditions in the dry/wet spinning process, etc., to change and The delayed stereotyping effect on the inner and outer cortex is enhanced to jointly prepare a hollow fiber membrane having high flux, high selectivity and good cortical structure.

5. The present invention applies a hollow fiber membrane made by the hollow fiber membrane preparation technology of the aforementioned controllable skin layer to pervaporation to perform experiments on hollow fiber membranes prepared by changing various parameters at the same temperature and medium. In order to further optimize the parameter setting for further practical use, a hollow fiber membrane having high flux, high selectivity and good cortical structure can be more effectively prepared.

In summary, the embodiments of the present invention can achieve the expected functions, and the specific structures disclosed therein have not been seen in similar products, nor have they been disclosed before the application, and have fully complied with the requirements and requirements of the Patent Law. If you apply for an invention patent in accordance with the law, you are welcome to review it and grant a patent.

(1). . . Penetration chamber

(2). . . O-ring

(3). . . Hollow fiber membrane

(4). . . collector

First Figure: Flow chart of the present invention

Fig. 2 is a microscopic enlarged view showing the variation of the chloroform concentration of the hollow fiber membrane process of the present invention

Fig. 3 is a microscopic enlarged view of the process pressure of the hollow fiber membrane of the present invention

Fig. 4 is a graph showing the variation of the spinning solution concentration of the hollow fiber membrane process of the present invention

Fig. 5 is a microscopic enlarged view of the variation of the spinning solution in the hollow fiber membrane process of the present invention

Fig. 6 is a microscopic enlarged view of the process of hollow fiber membranes of the present invention with different gas distances

Fig. 7 is a graph showing the phase separation rate of the external coagulant of different polarities in the process of hollow fiber membrane process of the present invention

Figure 8: Microscopic enlarged view of the external coagulant with different polarities in the process of hollow fiber membrane process of the present invention

Figure 9: Cortical thickness curve of external coagulant with different polarities in the process of hollow fiber membrane process of the present invention

Fig. 10 is a graph showing the thickness of the cortical layer of different polar core liquids in the process of hollow fiber membrane process of the present invention

Eleventh drawing: microscopic enlarged view of the hollow fiber membrane process variation of the present invention

Figure 12: Schematic diagram of the pervaporation apparatus of the present invention

Figure 13: Schematic diagram of the overall pervaporation apparatus of the present invention

Figure 14: The pervaporation curve of the hollow fiber membrane with different chloroform concentration

Fifteenth Figure: The pervaporation curve of the hollow fiber membrane with different casting pressures according to the present invention

Figure 16: The pervaporation curve of the hollow fiber membrane with different flow rates of the spinning solution according to the present invention

Figure 17: The pervaporation curve of the hollow fiber membrane with different spinning solution concentrations according to the present invention

Figure 18: The pervaporation curve of the hollow fiber membrane with different gas distances according to the present invention

Figure 19: Pervaporation curve of hollow fiber membranes with chloroform added and varying gas distances according to the present invention

Fig. 20 is a graph showing the pervaporation curve of a hollow fiber membrane of a different polarity external coagulant according to the present invention

Twenty-first graph: the pervaporation curve of the hollow fiber membrane of different polar core liquids according to the present invention

Claims (10)

A hollow fiber membrane preparation technology capable of controlling a cortex comprises the following steps: A. Configuring a casting solution: adding one of a polyfluorene [PSF] polymer and a sulfonated polyfluorene [SO ₃ H-PSF] Nitro-methyltetrahydropyrrolidone [NMP] to prepare a high concentration spinning solution of the desired concentration; B. Preparation of a spinning solution: adding a core liquid to the spinning solution, setting the flow rate of the core liquid and casting Film pressure; C. Spin film formation: The spinning solution is spun in a spinning device, so that the spinning solution and the core liquid are squeezed out from the spinning nozzle, and then enter the coagulant to solidify the hollow fiber membrane. The hollow fiber membrane preparation technology capable of controlling the cortex according to the first aspect of the patent application, wherein the spinning solution step further adds chloroform [CHCl ₃ ] to the spinning solution. The method for preparing a hollow fiber membrane capable of controlling a skin layer according to the second aspect of the invention, wherein the step of preparing the spinning solution step comprises at least water, methanol, ethanol, n-propanol, n-butanol and positive One of the hexanes. The method for preparing a hollow fiber membrane capable of controlling a cortex according to the first aspect of the invention, wherein the coagulant used in the spinning film forming step comprises at least water, methanol, ethanol, n-propanol and n-butanol. one. The method for preparing a hollow fiber membrane capable of controlling a cortex according to claim 4, wherein the step of preparing the spinning solution comprises at least water, methanol, ethanol, n-propanol, n-butanol and One of the hexanes. The method for preparing a hollow fiber membrane capable of controlling a skin layer according to any one of claims 1 to 5, wherein the spinning film forming step is performed after the spinning solution and the core liquid are squeezed out by the spinning nozzle. After a period of air distance, it enters the coagulant and solidifies into a film. The hollow fiber membrane preparation technology capable of controlling the skin layer according to the sixth aspect of the patent application, wherein the hollow fiber membrane preparation technology of the controllable skin layer further comprises the step of packaging the hollow fiber membrane after the spinning film formation, The plurality of hollow fiber membranes are assembled into a bundle, and further sleeved in a circular hole formed in the base to form a module. The hollow fiber membrane preparation technology capable of controlling the cortex according to the first aspect of the patent application, wherein the hollow fiber membrane preparation technology of the controllable skin layer further comprises the step of packaging the hollow fiber membrane after the spinning film formation, The plurality of hollow fiber membranes are assembled into a bundle, and further sleeved in a circular hole formed in the base to form a module. The hollow fiber membrane preparation technology capable of controlling the cortex according to the first aspect of the invention, wherein the hollow fiber membrane preparation technology of the controllable skin layer further comprises the step of preparing the membrane material, before the step of disposing the casting membrane solution Poly (PSF) polymer is added to chloroform [CHCl ₃ ] to be dissolved, then chlorosulfonic acid and chloroform [CHCl ₃ ] are mixed to form a chlorosulfonic acid solution, and the chlorosulfonic acid solution is added to the polymer solution. Methanol was then added to make a sulfonated polyfluorene [SO ₃ H-PSF]. A hollow fiber membrane pervaporation application method capable of controlling a cortex is provided with a pervaporation device, and the pervaporation device is provided with a permeation chamber, and the permeation chamber is divided into two chambers, and the aforementioned patent application scope is first The hollow fiber membrane formed by the hollow fiber membrane preparation technology capable of controlling the cortex is disposed between the two chambers, and the feed solution is directly contacted with the fiber membrane to penetrate into the hollow portion of the membrane by the surface of the hollow fiber membrane, and then The outlet end of the hollow fiber membrane is separated, and the substance permeating the membrane is collected by a collector equipped with a coolant, and the permeate is thawed, and the weight of the permeated hollow fiber membrane is measured by a gravimetric method and a gas chromatography analyzer. concentration.